Semiconductor light emitting device having multi-cell array and method for manufacturing the same

ABSTRACT

A semiconductor light emitting device includes a substrate and a plurality of light emitting cells arranged on the substrate. Each of the light emitting cells includes a first-conductivity-type semiconductor layer, a second-conductivity-type semiconductor layer, and an active layer disposed therebetween to emit blue light. An interconnection structure electrically connects the first-conductivity-type and the second-conductivity-type semiconductor layers of one light emitting cell to the first-conductivity-type and the second-conductivity-type semiconductor layers of another light emitting cell. A light conversion part is formed in a light emitting region defined by the light emitting cells and includes a red and/or a green light conversion part respectively having a red and/or a green light conversion material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/034,136filed on Feb. 24, 2011, which in turn claims the benefit of KoreanApplication Nos. 10-2010-0018259, filed on Feb. 26, 2010 and10-2010-0085707, filed on Sep. 1, 2010, the disclosures of whichApplications are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor light emitting device,and more particularly, to a semiconductor light emitting device, inwhich a plurality of light emitting cells are arranged, and a method formanufacturing the same.

2. Description of the Related Art

In general, semiconductor light emitting diodes (LEDs) are advantageousfor light sources in terms of power, efficiency and reliability.Therefore, semiconductor LEDs are being actively developed ashigh-power, high-efficiency light sources for various illuminationapparatuses as well as for a backlight unit of a display device. For thecommercialization of such semiconductor LEDs as illumination lightsources, it is necessary to increase their efficiency and reduce theirproduction cost while increasing their power to a desired level.

However, a high-power LED using a high rated current may have low lightefficiency due to a high current density, when compared to a low-powerLED using a low-rated current. Specifically, if a rated current isincreased to obtain high luminous flux in an LED chip of the same areain order to obtain high power, the light efficiency may be degraded dueto an increase in the current density. Also, the light efficiencydegradation is accelerated due to heat generation by the device.

To solve these problems, there has been proposed a high-power lightemitting device in which a plurality of low-power LED chips aredie-bonded at a package level and the chips thereof are connected bywire bonding. According to this approach, since the low-power LED chipshaving a relatively small size are used, current density is furtherreduced and thus an overall light efficiency is increased, as comparedto a case of using high-power LED chips having a large size. However, asthe number of wire bondings increases, manufacturing costs increase andmanufacturing processes become complicated. In addition, a fail rate dueto a wire open condition increases. When the chips are connected bywires, it is difficult to implement a complicated serial-parallelinterconnection structure. Due to the space occupied by the wires, it isdifficult to achieve the miniaturization of the package. Moreover, thereis a limit on the number of chips which are mountable in a singlepackage.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a semiconductor lightemitting device which can improve light efficiency by increasing currentdensity per unit area, and can emit white light having high colorrendering.

An aspect of the present invention also provides a semiconductor lightemitting device, which can obtain high-efficiency white light withoutusing phosphors, and a method for manufacturing the same.

An aspect of the present invention also provides a semiconductor lightemitting device which can ensure a sufficient light emitting area when aplurality of light emitting cells are provided therein.

According to an aspect of the present invention, there is provided asemiconductor light emitting device including: a substrate; a pluralityof light emitting cells arranged on the substrate, each of the lightemitting cells including a first-conductivity-type semiconductor layer,a second-conductivity-type semiconductor layer, and an active layerdisposed therebetween to emit blue light; an interconnection structureelectrically connecting at least one of the first-conductivity-typesemiconductor layer and the second-conductivity-type semiconductor layerof the light emitting cell to at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of another light emittingcell; and a light conversion part formed in at least a portion of alight emitting region defined by the plurality of light emitting cells,the light conversion part including at least one of a red lightconversion part having a red light conversion material and a green lightconversion part having a green light conversion material.

The light conversion part may not be formed in a portion of the lightemitting region.

The light conversion part may include at least one of a phosphor and aquantum dot.

The first-conductivity-type semiconductor layer of at least one of theplurality of light emitting cells may be electrically connected to thesecond-conductivity-type semiconductor layer of another light emittingcell.

The first-conductivity-type semiconductor layer of at least one of theplurality of light emitting cells may be electrically connected to thefirst-conductivity-type semiconductor layer of another light emittingcell.

The second-conductivity-type semiconductor layer of at least one of theplurality of light emitting cells may be electrically connected to thesecond-conductivity-type semiconductor layer of another light emittingcell.

The first-conductivity-type semiconductor layers of the plurality oflight emitting cells may be integrally formed.

One of the red light conversion part and the green light conversion partmay be formed at each of the light emitting cells.

One of the red light conversion part and the green light conversion partmay be integrally formed with respect to two or more of the plurality oflight emitting cells.

The light conversion part may be formed along the surfaces of the lightemitting cells.

The light conversion part may include the red light conversion part andthe green light conversion part, the plurality of light emitting cellsmay be divided into a red group including one or more cells in which thered light conversion part is formed, a green group including one or morecells in which the green light conversion part is formed, and a bluegroup including one or more cells in which the red light conversion partand the green light conversion part are not formed, and thesemiconductor light emitting device may further include three pairs ofpads connected to the red group, the green group, and the blue group,respectively.

Currents applied through the pads to the red group, the green group, andthe blue group may be independently controlled.

According to another aspect of the present invention, there is provideda semiconductor light emitting device including: a substrate; aplurality of light emitting cells arranged on the substrate, each of thelight emitting cells including a first-conductivity-type semiconductorlayer, a second-conductivity-type semiconductor layer, and an activelayer disposed therebetween to emit blue light; an interconnectionstructure electrically connecting at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of the light emitting cellto at least one of the first-conductivity-type semiconductor layer andthe second-conductivity-type semiconductor layer of another lightemitting cell; and a light conversion part formed in a light emittingregion defined by the plurality of light emitting cells, the lightconversion part including at least one of a red light conversionmaterial and a green light conversion material, wherein the lightconversion part is divided into a plurality of groups having a differentmixture ratio of at least one of the red light conversion material andthe green light conversion material.

According to another aspect of the present invention, there is provideda semiconductor light emitting device including: a package substrate; aplurality of multi-chip devices arranged on the package substrate, eachof the multi-chip devices including a first-conductivity-typesemiconductor layer, a second-conductivity-type semiconductor layer, andan active layer disposed therebetween to emit blue light; aninterconnection structure electrically connecting at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of the light emitting cellto at least one of the first-conductivity-type semiconductor layer andthe second-conductivity-type semiconductor layer of another lightemitting cell; and a plurality of light conversion parts disposed onlight paths of the multi-chip devices, the light conversion partsincluding at least one of a red light conversion material and a greenlight conversion material, wherein the light conversion parts aredivided into a plurality of groups having a different mixture ratio ofat least one of the red light conversion material and the green lightconversion material.

The light conversion parts may further include a yellow light conversionmaterial, and the light conversion parts are divided into a plurality ofgroups having a different mixture ratio of at least one of the red lightconversion material, the green light conversion material, and the yellowlight conversion material.

The semiconductor light emitting device may further include a pluralityof pads connected to the plurality of groups.

Currents applied through the plurality of pads to the plurality ofgroups may be independently controlled.

The light conversion part may include a dam part, and the inside of thedam part may be filled with the optical conversion material.

The dam part may include the same material as the optical conversionmaterial.

The dam part may be formed of the same material as the remaining portionof the light conversion part filled in the inside thereof.

According to another aspect of the present invention, there is provideda semiconductor light emitting device including: a substrate; aplurality of light emitting cells arranged on the substrate, each of thelight cells including a first-conductivity-type semiconductor layer, asecond-conductivity-type semiconductor layer, and an active layerdisposed therebetween; and an interconnection structure electricallyconnecting at least one of the first-conductivity-type semiconductorlayer and the second-conductivity-type semiconductor layer of the lightemitting cell to at least one of the first-conductivity-typesemiconductor layer and the second-conductivity-type semiconductor layerof another light emitting cell, wherein a part of the light emittingcells emit red light, a part of the light emitting cells emit greenlight, and the others emit blue light.

The semiconductor light emitting device may further include a base layerformed between the substrate and the first-conductivity-typesemiconductor layers and connecting the first-conductivity-typesemiconductor layers of the light emitting cells.

The base layer may be formed of a first-conductivity-type semiconductormaterial.

The base layer may be formed of an undoped semiconductor material.

The first-conductivity-type semiconductor layers of the light emittingcells may be integrally formed.

According to another aspect of the present invention, there is provideda method for manufacturing a semiconductor light emitting device,including: forming a first light emitting structure by sequentiallygrowing a first-conductivity-type semiconductor layer, a first activelayer, and a second-conductivity-type semiconductor layer on a firstregion of a substrate; forming a second light emitting structure bysequentially growing a first-conductivity-type semiconductor layer, asecond active layer, and a second-conductivity-type semiconductor layeron a second region of a substrate; forming a third light emittingstructure by sequentially growing a first-conductivity-typesemiconductor layer, a third active layer, and asecond-conductivity-type semiconductor layer on a third region of asubstrate; and forming an interconnection structure to electricallyconnect the first to third light emitting structures, wherein one of thefirst to third active layers emits red light, another emits green light,and the other emits blue light.

Before forming the first light emitting structure, the method mayfurther include forming a mask layer having a first open region on thesubstrate, wherein the first light emitting structure is formed in thefirst open region.

Before forming the second light emitting structure, the method mayfurther include forming a mask layer having a second open region on thesubstrate, wherein the second light emitting structure is formed in thesecond open region.

Before forming the third light emitting structure, the method mayfurther include forming a mask layer having a third open region on thesubstrate, wherein the third light emitting structure is formed in thethird open region.

The first to third light emitting structures may not be contacted withone another.

Before forming the first to third light emitting structures, the methodmay further include forming a base layer on the substrate.

The base layer may be formed of a first-conductivity-type semiconductormaterial.

The base layer may be formed of an undoped semiconductor layer.

The process of growing the first-conductivity-type semiconductor layermay be a process of re-growing the first-conductivity-type semiconductorlayer on the base layer.

According to another aspect of the present invention, there is provideda method for manufacturing a semiconductor light emitting device,including: growing a first-conductivity-type semiconductor layer on asubstrate; growing first to third active layers in first to thirdregions of the first-conductivity-type semiconductor layer; growing asecond-conductivity-type semiconductor layer to cover the first to thirdactive layers; forming first to third light emitting structures byremoving a portion of the second-conductivity-type semiconductor layerso that the second-conductivity-type semiconductor layer correspondingto positions of the first to third active layers is left; and forming aninterconnection structure to electrically connect the first to thirdlight emitting structures, wherein one of the first to third activelayers emits red light, another emits green light, and the other emitsblue light.

The forming of the first to third light emitting structures may includeremoving a portion of the first-conductivity-type semiconductor layer sothat the first-conductivity-type semiconductor layer corresponding tothe positions of the first to third active layers is left.

According to another aspect of the present invention, there is provideda semiconductor light emitting device including: a plurality of lightemitting cells arranged on a conductive substrate, each of the lightemitting cells including a first-conductivity-type semiconductor layer,a second-conductivity-type semiconductor layer, an active layer formedtherebetween, wherein the second-conductivity-type semiconductor layeris directed to the conductive substrate and electrically connected tothe conductive substrate; and an interconnection structure electricallyconnecting the first-conductivity-type semiconductor layer of at leastone of the light emitting cells to the first-conductivity-typesemiconductor layer of other light emitting cells.

The semiconductor light emitting device may further include a reflectivemetal layer formed between the conductive substrate and the plurality oflight emitting cells.

The interconnection structure may be formed of a metal.

A portion of the interconnection structure which is formed on the topsurface of at least the first-conductivity-type semiconductor layer maybe formed of a transparent conductive material.

The semiconductor light emitting device may further include a barrierlayer formed between the conductive substrate and the plurality of lightemitting cells.

The barrier layer may be electrically connected to thesecond-conductivity-type semiconductor layers of the light emittingcells.

The plurality of light emitting cells may be electrically connected inparallel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic plan view illustrating a semiconductor lightemitting device according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along line A-A′ of FIG.1;

FIG. 3 is an equivalent circuit diagram illustrating a connection oflight emitting cells in the semiconductor light emitting device of FIG.1;

FIG. 4 is a schematic cross-sectional view illustrating a modificationof the semiconductor light emitting device of FIG. 1;

FIG. 5 is a schematic cross-sectional view illustrating aninterconnection structure of light emitting cells which can be employedin another modification of the semiconductor light emitting device ofFIG. 1;

FIG. 6 is an equivalent circuit diagram illustrating an AC-driven devicewhich can be obtained by the interconnection structure of FIG. 5;

FIG. 7 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 8 is an equivalent circuit diagram illustrating a connection oflight emitting cells in the semiconductor light emitting device of FIG.7;

FIG. 9 is a schematic plan view illustrating a modification of thesemiconductor light emitting device of FIG. 7;

FIG. 10 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 11 is an equivalent circuit diagram illustrating a connection oflight emitting cells in the semiconductor light emitting device of FIG.10;

FIG. 12 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 13 is a schematic plan view illustrating alight emitting deviceaccording to another embodiment of the present invention;

FIG. 14 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 15 is a schematic cross-sectional view taken along line B-B′ ofFIG. 14;

FIG. 16 is a schematic cross-sectional view taken along line D-D′ ofFIG. 14;

FIGS. 17 through 20 are cross-sectional views explaining a method formanufacturing the semiconductor light emitting device of FIG. 14according to an embodiment of the present invention;

FIG. 21 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 22 is a schematic cross-sectional view taken along line E1-E1′ ofFIG. 21;

FIG. 23 is a schematic cross-sectional view illustrating a modificationof the semiconductor light emitting device of FIG. 21;

FIG. 24 is a schematic cross-sectional view illustrating a modificationof the semiconductor light emitting device of FIG. 21;

FIGS. 25 through 28 are cross-sectional views explaining a method formanufacturing the semiconductor light emitting device of FIG. 21according to an embodiment of the present invention;

FIG. 29 is a schematic configuration diagram illustrating the exemplaryuse of the semiconductor light emitting device according to theembodiment of the present invention;

FIG. 30 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention;

FIG. 31 is a schematic cross-sectional view taken along line A-A′ in thesemiconductor light emitting device of FIG. 30; and

FIGS. 32 through 34 are cross-sectional views explaining a method formanufacturing a semiconductor memory device according to anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Exemplary embodiments of the present invention will now be described indetail with reference to the accompanying drawings. The invention may,however, be embodied in many different forms and should not be construedas being limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the thicknesses of layers andregions are exaggerated for clarity. Like reference numerals in thedrawings denote like elements, and thus their description will beomitted.

FIG. 1 is a schematic plan view illustrating a semiconductor lightemitting device according to an embodiment of the present invention.FIG. 2 is a schematic cross-sectional view taken along line A-A′ ofFIG. 1. FIG. 3 is an equivalent circuit diagram illustrating aconnection of light emitting cells in the semiconductor light emittingdevice of FIG. 1. FIG. 4 is a schematic cross-sectional viewillustrating a modification of the semiconductor light emitting deviceof FIG. 1.

Referring to FIGS. 1 and 2, the semiconductor light emitting device 100according to the embodiment of the present invention includes asubstrate 101 and a plurality of light emitting cells C arranged on thesubstrate 101. The light emitting cells C are electrically connectedtogether by an interconnection structure 106. In this case, the term“light emitting cell” represents a semiconductor multilayer structurehaving an active layer region, which is distinguished from other cells.In this embodiment, twenty-five light emitting cells are arranged in a5×5 pattern; however, the number and arrangement of the light emittingcells C may be variously changed. As an additional element, first andsecond pads 107 a and 107 b for the application of external electricsignals may be formed on the substrate 101. In this embodiment, the pads107 a and 107 b directly contact the light emitting cells C. However, inanother embodiment, the pads 107 a and 107 b and the light emittingcells may be spaced apart from one another and connected together by theinterconnection structure 106. In this embodiment, in which the cell isseparated into the plurality of light emitting cells C, current densityper unit area may be further reduced than in a case in which a singlecell is used. Hence, the luminous efficiency of the semiconductor lightemitting device 100 may be improved.

As illustrated in FIG. 2, each of the light emitting cells C1, C2 and C3includes a first-conductivity-type semiconductor layer 102, an activelayer 103, and a second-conductivity-type semiconductor layer 104, whichare formed on the substrate 101. As illustrated in FIG. 3, the lightemitting cells C1, C2 and C3 are connected in series by theinterconnection structure 106. In this case, a transparent electrode 105formed of a transparent conductive oxide may be disposed on thesecond-conductivity-type semiconductor layer 104. In the seriesconnection structure of the light emitting cells C1, C2 and C3, thesecond-conductivity-type semiconductor layer 104 of the first lightemitting cell C1 and the first-conductivity-type semiconductor layer 102of the second light emitting cell C2 may be connected together. Inaddition to the series connection, a parallel connection or aseries-parallel connection can also be used herein, which will bedescribed later. In this embodiment, the interconnection structure 106is not a wire and is formed along the surfaces of the light emittingcells C1, C2 and C3 and the substrate 101, and an insulation part 108may be disposed between the light emitting cells C1, C2 and C3 and theinterconnection structure 106 to thereby prevent unintended electricalshorting. In this case, the insulation part 108 may be formed of amaterial known in the art, such as silicon oxide or silicon nitride. Inthis embodiment, since wires are not used as the structure forelectrical connection between the cells, the probability of electricalshorting may be reduced and the ease of the interconnection process maybe improved.

A substrate having electrical insulation properties may be used as thesubstrate 101 and thus the light emitting cells C may be electricallyisolated from one another. In a case in which a conductive substrate isused, it may be used by depositing an insulation layer thereon. In thiscase, the substrate 101 may be a growth substrate for growing asingle-crystal semiconductor. In this regard, a sapphire substrate maybe used. The sapphire substrate is a crystal body having Hexa-Rhombo R3csymmetry. The sapphire substrate has a lattice constant of 13.001 Å in ac-axis orientation and a lattice constant of 4.758 Å in an a-axisorientation; and has a C(0001) plane, an A(1120) plane, and an R(1102)plane. In this case, the C plane of the sapphire substrate allows anitride thin film to be grown thereupon relatively easily and is stableeven at high temperatures, thus it is predominantly used as a substratefor the growth of a nitride semiconductor. In other cases, a substrateformed of SiC, GaN, ZnO, MgAl₂O₄, MgO, LiAlO₂, or LiGaO₂, may also beused.

The first-conductivity-type semiconductor layer 102 and thesecond-conductivity-type semiconductor layer 104 may be formed of anitride semiconductor having a composition of Al_(x)In_(y)Ga_((1-x-y))N(0≦x≦1, 0≦y≦1, 0≦x+y≦1), and may be doped with n-type impurity or p-typeimpurity. In this case, the first-conductivity-type semiconductor layer102 and the second-conductivity-type semiconductor layer 104 may begrown by a process known in the art, such as a Metal Organic ChemicalVapor Deposition (MOCVD) process, a Hydride Vapor Phase Epitaxy (HVPE)process, or a Molecular Beam Epitaxy (MBE) process. The active layer 103formed between the first-conductivity-type semiconductor layer 102 andthe second-conductivity-type semiconductor layer 104 emits light havinga predetermined level of energy by electron-hole recombination. Theactive layer 103 may have a structure in which a plurality of layershaving a composition of In_(x)Ga_(1-x)N (0≦x≦1) are laminated to adjusta band gap energy according to the content of indium (In). In this case,the active layer 103 may have a multi quantum well (MQW) structure inwhich a quantum barrier layer and a quantum well layer are alternatelylaminated, for example, an InGaN/GaN structure. Although not necessarilyrequired, a transparent layer formed of a transparent conducive oxidemay be formed on the second-conductivity-type semiconductor layer 104.The transparent electrode may serve to perform an ohmic contact andcurrent distribution function. Meanwhile, as will be described later,the light emitting cells C, each including the first-conductivity-typesemiconductor layer 102, the second-conductivity-type semiconductorlayer 104, and the active layer 103, may be obtained by a separategrowth or may be obtained by growing a light emitting lamination bodyand separating it into individual cells.

In this embodiment, the active layer 103 emits blue light, for example,light having a peak wavelength of about 430-480 nm. When viewed fromabove the plurality of light emitting cells C, red and green lightconversion parts 109R and 109G are formed in at least a portion of alight emitting region. In the case of FIG. 1, the light emitting regionmay be considered as a set of rectangular light emitting surfacesdefined by the light emitting cells C. The formation of the lightconversion parts in the light emitting region corresponds to anapplication of a material which can convert the wavelength of the lighton a path through which the light travels from the light emittingregion. For example, the red light conversion part 109R is formed on alight emitting surface of a part of the light emitting cells C (forexample, C1 of FIG. 2), and the green light conversion part 109G may beformed on a light emitting surface of at least a part of the others (forexample, C2 of FIG. 2). Accordingly, blue light emitted from the lightemitting cell C and light emitted from the red and green lightconversion parts 109R and 109G may be mixed to obtain white light.However, the red and blue light conversion parts 109R and 109G are notrequisite elements. In some embodiments, only one of the red and greenlight conversion parts 109R and 109G may be provided on the lightemitting surface of the light emitting cell C.

The red and green light conversion parts 109R and 109G may include aphosphor and/or a quantum dot. In this case, the red and green lightconversion parts 109R and 109G may be dispersed in a silicon resin andcoated on the surface of a light emitting structure; however, theinvention is not limited thereto. In this embodiment, since the lightconversion parts 109R and 109G are coated on the plurality of lightemitting cells C, a coating process may be applied to a relatively largearea. Therefore, as compared to a case of coating a phosphor material oneach unit chip, a case of forming the plurality of cells C in the singledevice and forming the light conversion parts 109R and 109G in the lightemitting region is advantageous in terms of process facilitation. Inthis embodiment, the area of the light conversion parts 109R and 109G iswider than the occupied area of the light emitting cell C. However, thelight emitting parts 109R and 109G may be formed to cover a portion ofthe surface of the light emitting cell C, for example, only the topsurface thereof, according to process conditions or necessity.

In addition, in this embodiment, one of the red and green lightconversion parts 109R and 109G is applied to each light emitting cell C.However, one of the red and green light conversion parts 109R and 109Gmay be formed over two or more light emitting cells C. Such a structuremay also be applied to the following embodiments. Furthermore, althoughit is illustrated in FIG. 2 that the light conversion parts 109R and109G are formed along the surface of the light emitting cell C and thusthey have a similar shape to that of the light emitting cell C, thelight conversion parts 109R and 109G may not be formed along the surfaceof the light emitting cell C and may be formed to have a dome shape asin a modification example of FIG. 4. Moreover, as in the modificationexample of FIG. 4, a single light conversion part 109R′ may beintegrally applied to two or more light emitting cells C1 and C2.

Examples of a red phosphor which can be used in the red light conversionpart 1098 include a nitride phosphor having a composition of MAlSiNx:Re(1≦x≦5) or a sulfide phosphor having a composition of MD:Re. M is atleast one selected from Ba, Sr, Ca, and Mg; D is at least one selectedfrom S, Se, and Te; and Re is at least one selected from Eu, Y, La, Ce,Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, F, Cl, Br, and I. Inaddition, examples of a green phosphor which can be used in the greenlight conversion part 109G include a silicate phosphor having acomposition of M₂SiO₄:Re, a sulfide phosphor having a composition ofMA₂D₄:Re, a phosphor having a composition of β-SiAlON:Re, and an oxidephosphor having a composition of MA′₂O₄:Re′. M is at least one selectedfrom Ba, Sr, Ca, and Mg; A is at least one selected from Ga, Al, and In;D is at least one selected from S, Se, and Te; A′ is at least oneselected from Sc, Y, Gd, La, Lu, Al, and In; Re is at least one selectedfrom Eu, Y, La, Ce, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, F, Cl,Br, and I; and Re′ is at least one selected from Ce, Nd, Pm, Sm, Tb, Dy,Ho, Er, Tm, Yb, F, Cl, Br, and I.

In addition, the quantum dot is a nano crystal particle having a coreand a shell. The core of the quantum dot has a size ranging from 2 nm to100 nm. By adjusting the size of the core, the quantum dot may be usedas a phosphor material which emits various colors, such as blue (B),yellow (Y), green (G), and red (R). The core-shell structureconstituting the quantum dot may be formed by a heterojunction of atleast two kinds of semiconductors selected from group II-VI compoundsemiconductors (ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, MgTe,etc.), group III-V compound semiconductors (GaN, GaP, GaAs, GaSb, InN,InP, InAs, InSb, AlAs, AlP, AlSb, AlS, etc.), or group IV semiconductors(Ge, Si, Pb, etc.). In this case, an organic ligand using a materialsuch as oleic acid may be formed in the outer shell of the quantum dotin order to terminate the molecular bond of the shell surface, tosuppress the agglomeration of the quantum dot, to improve the dispersionwithin a resin, such as silicon resin or an epoxy resin, or to improvethe function of the phosphor.

Meanwhile, since there exists blue light which is not converted by thered and green light conversion parts 109R and 109G and pas ses throughthe red and green light conversion parts 109R and 109G, the red or greenlight conversion part 109R or 109G may be formed on the entire lightemitting surface of the light emitting cell C. However, in order toimprove a color rendering index or obtain white light having a low colortemperature, the light conversion parts may not be formed on a lightemitting surface of a part of the light emitting cells (for example, C2of FIG. 2). The number or arrangement of the red and green lightconversion parts 109R and 109G may be appropriately determined using abinning technique according to a color temperature and a color renderingindex required in the device. As such, in this embodiment, the singledevice can emit red light, green light, and blue light and the numberand arrangement thereof can be adjusted as necessary. Thus, thesemiconductor light emitting device according to the embodiment of thepresent invention is suitable for applying to an illumination apparatussuch as an emotional illumination apparatus.

FIG. 5 is a schematic cross-sectional view illustrating aninterconnection structure of light emitting cells which can be employedin another modification of the semiconductor light emitting device ofFIG. 1, and FIG. 6 is an equivalent circuit diagram illustrating anAC-driven device which can be obtained by the interconnection structureof FIG. 5. In the embodiment of FIG. 1, the light emitting cells areelectrically connected in series. Specifically, the connection of thelight emitting cells corresponds to an n-p connection. However, asillustrated in FIG. 5, the second-conductivity-type semiconductor layer104 of the first light emitting cell C1 may be electrically connected tothe second-conductivity-type semiconductor layer 104 of the second lightemitting cell C2, and the first-conductivity-type semiconductor layer102 of the second light emitting cell C2 may be electrically connectedto the first-conductivity-type semiconductor layer 102 of the thirdlight emitting cell C3. Such a connection corresponds to a connection ofthe semiconductor layers having the same polarity (p-p connection or n-nconnection). Such an interconnection structure can implement anAC-driven device as illustrated in FIG. 6. The circuit of FIG. 6 is aso-called ladder network circuit in which eleven light emitting cellscan emit light with respect to electric signals which are provided in aforward direction and a reverse direction.

FIG. 7 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention. FIG. 8 is an equivalent circuit diagram illustrating aconnection of light emitting cells in the semiconductor light emittingdevice of FIG. 7. FIG. 9 is a schematic plan view illustrating amodification of the semiconductor light emitting device of FIG. 7.

Referring to FIG. 7, the semiconductor light emitting device 200according to the embodiment of the present invention includes sixteenlight emitting cells C on a substrate 201. The sixteen light emittingcells C are arranged in a 4×4 pattern. In this case, the number andarrangement of the light emitting cells C may be modified. As in theforegoing embodiment, a red light conversion part 209R is formed at aportion of a light emitting region formed by the plurality of lightemitting cells C, and a green light conversion part 209G may be formedat a portion of the others. Accordingly, light emitted from the red andgreen light conversion parts 209R and 209G and blue light emitted fromthe light emitting cell C in which the red and green light conversionparts 209R and 209G are not formed may be mixed to emit white light.

First and second pads 207 a and 207 b are formed in other regions on thesubstrate 201 and electrically connected to a first-conductivity-typesemiconductor layer 202 and a second-conductivity-type semiconductorlayer of the light emitting cells C. In FIG. 7, thesecond-conductivity-type semiconductor layer is not illustrated, and atransparent electrode 205 formed thereon is illustrated. In thisembodiment, the light emitting cells C are configured to share thefirst-conductivity-type layer 202. That is, upon separation based on thelight emitting cells C, the first-conductivity-type semiconductor layer202 is not separated and it may be integrally formed over the entiretyof the light emitting cells C. A first interconnection structure 206 aconnected to the first pad 207 a extends from the first pad 207 b suchthat it is connected to the first-conductivity-type semiconductor layer202. Likewise, a second interconnection structure 206 b connected to thesecond pad 207 b extends from the second pad 207 b such that it isconnected to the second-conductivity-type semiconductor layer. Aconnection part m may be formed to connect the second-conductivity-typesemiconductor layers of the adjacent light emitting cells C. In thiscase, although not illustrated in FIG. 7, since the secondinterconnection structure 206 b and the connection part m need to beelectrically separated from the first-conductivity-type semiconductorlayer 202 or the active layer, an insulation material or an air bridgestructure may be disposed therebetween.

As illustrated in FIG. 8, due to such an electrical connectionstructure, the sixteen light emitting cells C are connected in parallel.Such a parallel connection structure may be useful as a high-power lightsource under a DC voltage. The semiconductor light emitting device 200′of FIG. 9 is similar to the embodiment of FIG. 1 in that thefirst-conductivity-type semiconductor layers 202 are provided to theindividual light emitting cells C, but the electrical connectionstructure thereof corresponds to the parallel connection structure ofFIG. 7. The first interconnection structure 206 a extending from thefirst pad 207 a is not directly connected to the light emitting cell Cbut is connected to the first-conductivity-type semiconductor layer 202of the light emitting cell C through the connection part m.

FIG. 10 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention, and FIG. 11 is an equivalent circuit diagram illustrating aconnection of light emitting cells in the semiconductor light emittingdevice of FIG. 10.

Referring to FIG. 10, the semiconductor light emitting device 300according to the embodiment of the present invention includes sixteenlight emitting cells C on a substrate 301. The sixteen light emittingcells C are arranged in a 4×4 pattern. In this case, the number andarrangement of the light emitting cells C may be modified. As in theforegoing embodiment, a red light conversion part 309R is formed at aportion of a light emitting region formed by the plurality of lightemitting cells C, and a green light conversion part 309G may be formedat a portion of the others. Accordingly, light emitted from the red andgreen light conversion parts 309R and 309G and blue light emitted fromthe light emitting cell C in which the red and green light conversionparts 309R and 309G are not formed may be mixed to emit white light. Inthis embodiment, first and second pads 307 a and 307 b are formed inother regions on the substrate 301 and electrically connected to afirst-conductivity-type semiconductor layer 302 and asecond-conductivity-type semiconductor layer of the light emitting cellsC. In FIG. 10, the second-conductivity-type semiconductor layer is notillustrated, and a transparent electrode 305 formed thereon isillustrated. That is, a first interconnection structure 306 a connectedto the first pad 307 a is connected to the second-conductivity-typesemiconductor layer provided in a part of the light emitting cells C.Likewise, a second interconnection structure 306 b connected to thesecond pad 307 b is connected to the first-conductivity-typesemiconductor layer of apart of the other light emitting cells C. Theother light emitting cells C which are not directly connected to thefirst and second interconnection structures 306 a and 306 b areconnected in series by a connection structure m. Accordingly, asillustrated in FIG. 11, a structure in which the series connection andthe parallel connection are mixed may be obtained.

FIGS. 12, 13 and 30 are schematic plan views illustrating semiconductorlight emitting devices according to other embodiments of the presentinvention. FIG. 31 is a schematic cross-sectional view taken along lineA-A′ of FIG. 30.

In the embodiment of FIG. 12, the semiconductor light emitting device400 includes twenty-four light emitting cells C on a substrate 401. Thetwenty-four light emitting cells C are arranged in a 4×6 pattern. Theplurality of light emitting cells C are divided into three groups: a redgroup RG, a green group GG, and a blue group BG. A red light conversionmaterial covering the light emitting cells C is formed in a lightemitting region corresponding to the red group RG. A green lightconversion material covering the light emitting cells C is formed in alight emitting region corresponding to the green group GG. A lightconversion material is not formed in a light emitting regioncorresponding to the blue group BG. Each of the red group RG, the greengroup GG, and the blue group BG includes eight light emitting cells C,and a series connection structure is formed therebetween. However, thenumber or electrical connection of the light emitting cells C may beappropriately modified. For example, the cells within single group RG,GG or BG may form a parallel structure or a series-parallel structure.As illustrated in FIG. 12, in order to uniformly mix different coloredlight, the red group RG, the green group GG, and the blue group BG maybe separately arranged in a plurality of regions so that they are mixedwith other groups, instead of being arranged to have the same kinds ofgroups in a single region. In this case, the connection structures m ofthe light emitting cells C belonging to different groups may be arrangedto overlap one another. To this end, an insulation material or an airbridge structure may be provided between the connection structures m ofthe corresponding region.

In this embodiment, the semiconductor light emitting device 400 includesthree pairs of pads. Specifically, first and second pads 407 a and 407 bconnected to the red group RG, first and second pads 407 a′ and 407 b′connected to the blue group BG, and first and second pads 407 a″ and 407b″ connected to the green group GG are arranged on the substrate 401.Currents applied through the three pairs of the pads to the red groupRG, the green group GG, and the blue group BG may be independentlycontrolled. Accordingly, an amount of light emitted from each group maybe controlled by adjusting the intensity of the currents applied to thered group RG, the green group GG, and the blue group BG. Hence, thecolor temperature and the color rendering index of white light may bechanged to a desired level. For example, warm white light may beobtained by relatively increasing the intensity of the light emittedfrom the red group RG. In a similar manner, cool white light may beobtained by relatively increasing the intensity of the light emittedfrom the blue group BG. In addition, other colors except for white lightmay be implemented by the by-group current control method. Thesemiconductor light emitting device according to the embodiment of thepresent invention may be used in an emotional illumination apparatus.

In the embodiment of FIG. 13, the semiconductor light emitting device400′ includes twenty-four light emitting cells C on a substrate 401. Thetwenty-four light emitting cells C are arranged in a 4×6 pattern in asimilar manner to the embodiment of FIG. 12. However, the plurality oflight emitting cells C are divided into three groups RGG1, RGG2, andRGG3, and a mixture of red and green light conversion materials coveringthe light emitting cells C are formed in light emitting regionscorresponding to the respective groups RGG1, RGG2 and RGG3. That is, inthis embodiment, the light conversion part applied to the single groupincludes two or more light conversion materials, for example, red andgreen light conversion materials. In this case, a mixture ratio of atleast one of the red and green light conversion materials in at leastone of the groups RGG1, RGG2 and RGG3 is different from that of theothers. Accordingly, different colored light may be mixed. In this case,the single light conversion part may include another material as well asthe red and green color light conversion materials. For example, thelight conversion part may include red, green and blue light conversionmaterials. Accordingly, the quality of white light may be furtherimproved.

As in the embodiment of FIG. 12, each of the groups RGG1, RGG2 and RGG3includes eight light emitting cells C, and a series connection structureis formed therebetween. However, the number or electrical connection ofthe light emitting cells C may be appropriately modified. As illustratedin FIG. 13, in order to uniformly mix different colored light, theplurality of groups RGG1, RGG2 and RGG3 may be separately arranged in aplurality of regions so that they are mixed with other groups, insteadof arranging the same kinds of the groups in a single region. In thiscase, the connection structures m of the light emitting cells Cbelonging to different groups may be arranged to overlap one another. Tothis end, an insulation material or an air bridge structure may beprovided between the connection structures m of the correspondingregion. In addition, three pairs of pads are provided on the substrate401. Specifically, first and second pads 407 a and 407 b connected tothe first group RRG1, first and second pads 407 a′ and 407 b′ connectedto the second group RGG2, and first and second pads 407 a″ and 407 b″connected to the third group RGG3 are arranged on the substrate 401.Currents applied through the three pairs of the pads to the plurality ofgroups RGG1, RGG2 and RGG3 may be independently controlled. Accordingly,the color temperature and the color rendering index of white light maybe changed to a desired level. As in this embodiment, the colortemperature and the color rendering index may be controlled moreprecisely in such a way that the currents applied to the respectivegroups RGG1, RGG2 and RGG3 are independently controlled by mixing two ormore light conversion materials and differently applying the mixtureratios of the light conversion materials to the respective groups RGG1,RGG2 and RGG3.

Meanwhile, although it has been described in the embodiments of FIGS. 12and 13 that the color temperature of white light is controlled withinthe single multi-chip, the color temperature of white light may also becontrolled at a package level. In the embodiments of FIGS. 30 and 31,the semiconductor light emitting device 400″ includes a plurality ofmulti-chip devices 400G1 and 400G2 arranged on a package substrate 410.As illustrated in FIG. 31, each of the multi-chip devices 400G1 and400G2 has a structure in which a plurality of light emitting cells areconnected together. In this case, each of the multi-chip devices 400G1and 400G2 may form the same light emitting cell connection structure asdescribed in the previous embodiment. That is, the multi-chip devices400G1 and 400G2 have a structure in which the plurality of lightemitting cells are arranged on the substrate 401, and each of the lightemitting cells includes a first-conductivity-type semiconductor layer402, an active layer 403, a second-conductivity-type semiconductor layer404, and a transparent electrode 405. In addition, the interconnectionstructure 406 is not a wire and is formed along the surfaces of thelight emitting cells and the substrate 401, and an insulation part 408may be disposed between the light emitting cells and the interconnectionstructure 406 to thereby prevent unintended electrical shorting.

In this embodiment, the multi-chip devices 400G1 and 400G2 include redand green light conversion materials having different mixture ratios, asin the embodiments of FIGS. 12 and 13. In this embodiment, themulti-chips are divided into two groups 400G1 and 400G2. Therefore, thetotal color temperature and color rendering index of the semiconductorlight emitting device may be precisely controlled by independentlyadjusting the currents applied to the groups 400G1 and 400G2. Meanwhile,in this embodiment, the light conversion part includes a dam part 411.The inside of the dam part 411 is filled with a light conversionmaterial 412. The dam part 411 may be formed by a dam and fill process.The dam and fill process is a process which forms the dam part 411 tosurround the light emitting cell in the package substrate 410 or thelight emitting cell substrate 401 and fills the dam part 411 with thelight conversion material 412. In this embodiment, the dam part 411 mayinclude the same material as the light conversion material 412.Furthermore, the dam part 411 itself may be formed of the same materialas the filled part thereof. That is, the dam part 411 may furtherinclude a phosphor as well as a resin and a filler (Al₂O₃, SiO₂, TiO₂,etc.). Accordingly, a thixotropy thereof is improved to facilitate theformation of the dam. In addition, light may be emitted to the outsidethrough the dam part 411. Moreover, since the wavelength conversion maybe performed, it can be expected that light loss caused by the dam part411 will be minimized and light efficiency and light orientationproperty will be improved.

FIG. 14 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention. FIG. 15 is a schematic cross-sectional view taken along lineB-B′ of FIG. 14. FIG. 16 is a schematic cross-sectional view taken alongline D-D′ of FIG. 15.

Referring to FIGS. 14 through 16, the semiconductor light emittingdevice 500 includes a plurality of light emitting cells C arranged on asubstrate 501. Each of the light emitting cells C includes afirst-conductivity-type semiconductor layer 502, an active layer 503,and a second-conductivity-type semiconductor layer 504. In addition, atransparent electrode 505 may be further disposed on thesecond-conductivity-type semiconductor layer 504. In this embodiment, abase layer 502′ connecting the first-conductivity-type semiconductorlayers 502 provided at the light emitting cells C is disposed betweenthe light emitting cells and the substrate 501. The base layer 502′ maybe integrally formed over the entirety of the light emitting cells. Thebase layer 502′ may be formed of a first-conductivity-type semiconductormaterial or an undoped semiconductor material. As will be describedlater, the base layer 502′ may serve as a seed layer for re-growing thefirst-conductivity-type semiconductor layer 502. In a case in which thebase layer 502′ is formed of the first-conductivity-type semiconductormaterial, the first-conductivity-type semiconductor layer is shared bythe light emitting cells C. Accordingly, the light emitting cells C areelectrically connected in parallel. In this case, the active layer 503may be grown without re-growing the first-conductivity-typesemiconductor layer 502. Furthermore, in some cases, the base layer 502′may not be formed. In this case, the light emitting cells C may bedirectly formed on the substrate 501.

A first pad 507 a is formed on the base layer 502′, and a firstinterconnection structure 506 a extends from the first pad 507 a and isconnected to the first-conductivity-type semiconductor layer 502. Inaddition, a second pad 507 b is formed on the first-conductivity-typesemiconductor layer 502, and a second interconnection structure 506 bextends from the second pad 507 b and is connected to thesecond-conductivity-type semiconductor layer 504. However, since thesecond pad 507 b and the second interconnection structure 506 b need tobe electrically separated from the first-conductivity-type semiconductorlayer 502 and the active layer 503, an insulation part 508 may bedisposed therebetween. Meanwhile, although the first pad 507 a and thesecond pad 507 b are formed on the first-conductivity-type semiconductorlayer 502, they may be formed similarly to the foregoing embodiment.That is, the first pad 507 a and the second pad 507 b may be formed in apredetermined region of the substrate 501 in which thefirst-conductivity-type semiconductor layer 502 is not formed.

In this embodiment, the semiconductor light emitting device 500 includesthree or more kinds of light emitting cells C. A first light emittingcell C1 emits red light, a second light emitting cell C2 emits greenlight, and a third light emitting cell C3 emits blue light. That is, thesingle device can emit red light, green light, and blue light. Since thenumber and arrangement of the light emitting cells C can be adjusted asnecessary, it is suitable for applying to an illumination apparatus suchas an emotional illumination apparatus. To this end, the compositions ofthe active layers 503R, 503G and 503B of the first, second and thirdlight emitting cells C1, C2 and C3 are adjusted so that the activelayers 503R, 503G and 503B have different band gap energies to therebyemit different colored light. As will be described later, when the lightemitting cells C1, C2 and C3 are formed by different re-growthprocesses, growth conditions of the active layers 503R, 503G and 503Bprovided at the first, second and third light emitting cells C1, C2 andC3 may be easily adjusted. In addition, since the light emitting cells Cemitting the red, green and blue light are provided, the lightconversion part may not be separately formed on the light emittingsurfaces of the light emitting cells C. Hence, light loss caused by aphosphor or a quantum dot may be reduced.

FIGS. 17 through 20 are cross-sectional views explaining a method formanufacturing the semiconductor light emitting device of FIG. 14according to an embodiment of the present invention. As illustrated inFIG. 17, a base layer 502′ is grown on a substrate 501. As describedabove, the base layer 502′ may be formed of a first-conductivity-typesemiconductor material or an undoped semiconductor material. Forexample, the base layer 502′ may be formed of a nitride semiconductor.In this case, the base layer 502′ may be formed using a semiconductorthin film growth process known in the art, such as an MOCVD process, anHVPE process, or an MBE process.

As illustrated in FIG. 18, a mask layer 510 having an open regionexposing a portion of the base layer 502′ is formed on the substrate501. The open region is provided as a region for forming a lightemitting cell through a re-growth process. The mask layer 510 may beformed of a material, such as silicon oxide or silicon nitride, througha deposition process or a sputtering process. In addition, the openregion of the mask layer 510 may be formed using a photoresist processknown in the art. As illustrated in FIG. 19, a light emitting cell isformed by sequentially growing a first-conductivity-type semiconductorlayer 502, an active layer 503R, and a second-conductivity-typesemiconductor layer 504 on the base layer 502 through the open region.Although the order of growth is not specifically limited, the activelayer 503R emitting red light may be grown through this growth process.

As illustrated in FIG. 20, another open region is formed in the masklayer 510. a light emitting cell including a first-conductivity-typesemiconductor layer 502, an active layer 503G emitting green light, anda second-conductivity-type semiconductor layer 504 is formed on the baselayer 502′. A light emitting cell including a first-conductivity-typesemiconductor layer 502, an active layer 503B emitting blue light, and asecond-conductivity-type semiconductor layer 504 is formed on the baselayer 502′. In this step, the light emitting cells may be independentlyarranged without contacting one another. Although not illustrated, atransparent electrode may be formed on the second-conductivity-typesemiconductor layer 504. An interconnection structure is formed toelectrically connect the light emitting cells, thereby obtaining astructure of FIG. 14. In the above-described method for manufacturingthe semiconductor light emitting device, an etching process is not usedfor separation into the light emitting cells C. Instead, the re-growthof the semiconductor layer is used to spontaneously separate the lightemitting cells. In addition, the first-conductivity-type semiconductorlayer 502 may not be etched in order to connect the interconnectionstructure to the first-conductivity-type layer 502. Accordingly, it ispossible to prevent the damage of the light emitting cells C which iscaused during the etching process. Since the area of the active layer503 is sufficiently ensured, the luminous efficiency of thesemiconductor light emitting device can be improved.

FIGS. 32 through 34 are cross-sectional views explaining a method formanufacturing a semiconductor memory device according to anotherembodiment of the present invention. As illustrated in FIG. 32, afirst-conductivity-type semiconductor layer 502 is grown on a substrate501, and first to third active layers 503R, 503B and 503G are formed infirst to third regions of the first-conductivity-type semiconductorlayer 502. As in the foregoing embodiment, the first to third activelayers 503R, 503B and 503G emit red light, blue light, and green light,respectively. In this case, the first to third active layers 503R, 503Band 503G may be grown using a mask layer 510 with an open region havingan appropriate shape. As illustrated in FIG. 33, asecond-conductivity-type semiconductor layer 504 is grown to cover thefirst to third active layers 503R, 503B and 503G. Thesecond-conductivity-type semiconductor layer 504 may be integrallyformed while covering the top and side surfaces of the first to thirdactive layers 503R, 503B and 503G.

As illustrated in FIG. 34, a light emitting structure (light emittingcell) separating process is performed. That is, first to third lightemitting structures are formed by removing a portion of thesecond-conductivity-type semiconductor layer 504 so that thesecond-conductivity-type semiconductor layer 504 corresponding topositions of the first to third active layers 503R, 503B and 503G isleft. In this case, as illustrated in FIG. 34, thefirst-conductivity-type semiconductor layer 502 may not be removed.Accordingly, the light emitting structures may be connected in parallel.Alternatively, in order to apply another connection structure, a portionof the first-conductivity-type semiconductor layer 502 may be removed sothat the first-conductivity-type semiconductor layer 502 correspondingto the positions of the first to third active layers 503R, 503B and 503Gis left. Although not illustrated, a multi-chip device can beimplemented by forming an appropriate electrical interconnectionstructure between the light emitting structures.

FIG. 21 is a schematic plan view illustrating a semiconductor lightemitting device according to another embodiment of the presentinvention, and FIG. 22 is a schematic cross-sectional view taken alongline E1-E1′ of FIG. 21.

Referring to FIGS. 21 and 22, the semiconductor light emitting device600 includes a plurality of light emitting cells C arranged on aconductive substrate 606. Each of the light emitting cells C includes afirst-conductivity-type semiconductor layer 601, an active layer 602,and a second-conductivity-type semiconductor layer 603. A reflectivemetal layer 604 may be disposed between the light emitting cells C andthe conductive substrate 606, specifically, between thesecond-conductivity-type semiconductor layer 603 and the conductivesubstrate 606. The reflective metal layer 604 is not a requisite elementbut an optional element. An interconnection structure 607 forelectrically connecting the plurality of light emitting cells C isformed on the first-conductivity-type semiconductor layer 601. A pad 608connected to the interconnection structure 607 may be further provided.An external electric signal is applied through the pad 608. In thiscase, as illustrated in FIG. 22, the interconnection structure 607 isformed along the surfaces of the light emitting cells C1 and C2 toconnect the first-conductivity-type semiconductor layers 601 provided inthe two light emitting cells C1 and C2. The active layer 602, thesecond-conductivity-type semiconductor layer 603, the reflective metallayer 604, and the conductive substrate 606 may be electricallyseparated from one another by an insulation part 609. In thisembodiment, since the electrical connection structure of thesecond-conductivity-type semiconductor layer 603 can be performed by theconductive substrate 606, an additional interconnection structure neednot be formed. In addition, since the first-conductivity-typesemiconductor layer 601 or the second-conductivity-type semiconductorlayer 603 need not be mesa-etched, a sufficient light emitting area canbe ensured.

The conductive substrate 606 serves as a support body which supports thelight emitting structures in a subsequent process such as a laserlift-off process. The conductive substrate 606 may be formed of one ormore materials selected from Au, Ni, Al, Cu, W, Si, Se, and GaAs. Forexample, the conductive substrate 606 may be formed of a material inwhich Al is doped into Si. In this case, the conductive substrate 606may be formed by a plating process or a bonding process according to theselected material. The conductive substrate 606 is electricallyconnected to the second-conductivity-type semiconductor layer 603 ofeach light emitting cell C. Accordingly, in this embodiment, the lightemitting cells Care electrically connected in parallel. The reflectivemetal layer 604 may reflect light emitted from the active layer 602 inan upward direction of the device, that is, in a direction of thefirst-conductivity-type semiconductor layer 601. Furthermore, thereflective metal layer 604 may form an ohmic contact with thesecond-conductivity-type semiconductor layer 603 in consideration ofelectrical properties. Considering such a function, the reflective metallayer 604 may include Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, or Au. Inthis case, although not illustrated in detail, reflection efficiency canbe improved by employing the reflective metal layer 604 in a multilayerstructure. Examples of the reflective metal layer having the multilayerstructure include Ni/Ag, Zn/Ag, Ni/Al, Pd/Ag, Pd/Al, Ir/Ag, Ir/Au,Pt/Ag, Pt/Al, and Ni/Ag/Pt. Although it is illustrated that thereflective metal layer 604 is provided in each light emitting cells C,the reflective metal layer 604 may also be integrally formed over theentirety of the light emitting cells C.

FIGS. 23 and 24 are schematic cross-sectional views illustrating amodification of the semiconductor light emitting device of FIG. 21.Referring to FIG. 23, the semiconductor light emitting device 600′further includes a barrier layer 605 in the embodiment of FIG. 21. Thebarrier layer 605 may be integrally formed over the entirety of thelight emitting cells C1 and C2. The barrier layer 605 may be formedbetween the conductive substrate 606 and the light emitting cells C1 andC2 in order to prevent impacts or unintended diffusion of materialsduring a process of bonding the conductive substrate 606 to the lightemitting structure. The barrier layer 605 may be formed of TiW.Referring to FIG. 24, an interconnection structure 607′ of asemiconductor light emitting device 600″ may be divided into a metalregion 607 a and a transparent region 607 b. Light loss can be reducedby forming an upper region of at least a first-conductivity-typesemiconductor layer 601 as the transparent region 607 a. In this case,the transparent region 607 b of the interconnection structure 607′ maybe formed of transparent conductive oxide.

FIGS. 25 through 28 are cross-sectional views explaining a method formanufacturing the semiconductor light emitting device of FIG. 21according to an embodiment of the present invention. As illustrated inFIG. 25, a light emitting lamination body is formed by sequentiallygrowing a first-conductivity-type semiconductor layer 601, an activelayer 602, and a second-conductivity-type semiconductor layer 603 byusing one or more semiconductor layer growth processes, such as a MOCVDprocess, an HVPE process, and an MBE process. As illustrated in FIG. 26,an insulation part 609 having an open region is formed on thesecond-conductivity-type semiconductor layer 603, and a reflective metallayer 604 is formed to fill the open region. In this case, theinsulation part 609 and the reflective metal layer 604 may be formedusing a deposition process or a sputtering process known in the art.

As illustrated in FIG. 27, a conductive substrate 606 is formed on thereflective metal layer 604. For example, a bonding attachment layer (notshown) formed of an eutectic metal may be applied between the reflectivemetal layer 604 and the conductive substrate 606, and the conductivesubstrate 606 may be attached thereto. A growth substrate 610 isseparated from the light emitting lamination body. The growth substrate610 may be separated using a laser lift-off process or a chemicallift-off process. FIG. 27 illustrates a state in which the growthsubstrate 610 is removed, while being rotated by 180 degrees incomparison with FIG. 26.

As illustrated in FIG. 28, an inter-cell separation process is performedto remove a region between the light emitting cells C1 and C2, therebyforming a plurality of light emitting cells C1 and C2. In this case, theinter-cell separation process may be performed using a known etchingprocess such as an ICP-RIE process. During this process, the insulationpart 609 may serve as an etching barrier layer. Although notillustrated, an insulation part 609 is further formed on the surfaces ofthe light emitting cells C1 and C2, and an interconnection structure 607is formed to connect to the first-conductivity-type semiconductor layer601. In this manner, the semiconductor light emitting device 600illustrated in FIG. 21 is obtained.

Meanwhile, FIG. 29 is a schematic configuration diagram illustrating theexemplary use of the semiconductor light emitting device according tothe embodiment of the present invention. Referring to FIG. 29, anillumination apparatus 700 includes a light emitting module 701, asupport structure 704 on which the light emitting module 701 isdisposed, and a power supply 703. The light emitting module 701 includesone or more semiconductor light emitting devices 702 manufactured by themethods proposed in the embodiments of the present invention.Furthermore, the illumination apparatus 700 includes a feedback circuitwhich compares an amount of light emitted from the semiconductor lightemitting device 702 with a preset amount of light, and a memory devicewhich stores information on desired luminance or color rendering. Theillumination apparatus 700 may be used as indoor illumination, such aslamps or plate light, or outdoor illumination, such as streetlights orsigns. In addition, the illumination apparatus 700 may be used invarious means of transportation, for example, vehicles, such as ships orairplanes. Moreover, the illumination apparatus 700 will be widely usedin household appliances, such as TVs or refrigerators, and medicalappliances.

When the semiconductor light emitting devices according to exemplaryembodiments of the present invention are used, the current density perunit area is increased to improve the light extraction efficiencythereof. Furthermore, white light having high color rendering can beobtained.

In addition, the semiconductor light emitting devices according toexemplary embodiments of the present invention can obtainhigh-efficiency white light without using phosphors. Moreover, when thesemiconductor light emitting device are provided with a plurality oflight emitting cells, a sufficient light emitting area can be ensured.

While the present invention has been shown and described in connectionwith the exemplary embodiments, it will be apparent to those skilled inthe art that modifications and variations can be made without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

1-12. (canceled)
 13. A semiconductor light emitting device comprising: asubstrate; a plurality of light emitting cells arranged on thesubstrate, each light emitting cell of the plurality of light emittingcells including a first-conductivity-type semiconductor layer, asecond-conductivity-type semiconductor layer, and an active layerdisposed between the first-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer to emit blue light; aninterconnection structure electrically connecting at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of one light emitting cellof the plurality of light emitting cells to at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of another light emittingcell of the plurality of light emitting cells; and a light conversionpart disposed in a light emitting region defined by the plurality oflight emitting cells, the light conversion part including at least oneof a red light conversion material and a green light conversionmaterial, wherein the light conversion part is divided into a pluralityof groups having a different mixture ratio of at least one of the redlight conversion material and the green light conversion material,wherein the interconnection structure has a portion disposed on a topsurface and at least one of side surfaces of the one light emitting cellof the plurality of light emitting cells; and the light conversion partis disposed so as to cover at least the portion of the interconnectionstructure.
 14. A semiconductor light emitting device comprising: apackage substrate; a plurality of multi-chip devices arranged on thepackage substrate, each multi-chip device of the plurality of multi-chipdevices including a plurality of light emitting cells, each of theplurality light emitting cells includes a first-conductivity-typesemiconductor layer, a second-conductivity-type semiconductor layer, andan active layer disposed between the first-conductivity-typesemiconductor layer and the second-conductivity-type semiconductor layerto emit blue light; an interconnection structure electrically connectingat least one of the first-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of one light emitting cellof the plurality of light emitting cells to at least one of thefirst-conductivity-type semiconductor layer and thesecond-conductivity-type semiconductor layer of another light emittingcell of the plurality of light emitting cells; and a plurality of lightconversion parts disposed on light paths of the multi-chip devices, thelight conversion parts including at least one of a red light conversionmaterial and a green light conversion material, wherein the lightconversion parts are divided into a plurality of groups having adifferent mixture ratio of at least one of the red light conversionmaterial and the green light conversion material, wherein theinterconnection structure has a portion disposed on a top surface and atleast one of side surfaces of the one light emitting cell of theplurality of light emitting cells; and the light conversion part isdisposed so as to cover at least the portion of the interconnectionstructure.
 15. The semiconductor light emitting device of claim 13,wherein the light conversion parts further include a yellow lightconversion material, and the light conversion parts are divided into aplurality of groups having a different mixture ratio of at least one ofthe red light conversion material, the green light conversion material,and the yellow light conversion material.
 16. The semiconductor lightemitting device of claim 13, further comprising a plurality of padsconnected to the plurality of groups.
 17. The semiconductor lightemitting device of claim 16, wherein currents applied through theplurality of pads to the plurality of groups are independentlycontrolled.
 18. The semiconductor light emitting device of claim 13,wherein the light conversion part includes a dam part, and the inside ofthe dam part is filled with the optical conversion material.
 19. Thesemiconductor light emitting device of claim 18, wherein the dam partincludes the same material as the optical conversion material.
 20. Thesemiconductor light emitting device of claim 18, wherein the dam part isformed of the same material as the remaining portion of the lightconversion part filled in the inside thereof.